Recent increases in fuel costs and efficiency standards have prompted the use of improved construction materials in homes and office buildings. While the advent of these new construction materials has led to a reduction in energy consumption used by many HVAC systems, there is often an insufficient amount of fresh air available within the controlled structure. The lack of fresh air within the structure can lead to an excess amount of humidity and elevated levels of carbon dioxide, radon gasses, volatile organic compounds (VOC's), and other toxins, affecting the comfort and health of the occupants. In some circumstances, the lack of fresh air can also affect the ability of the HVAC system to function efficiently, increasing the operating cost of the system.
To counter these effects, many HVAC systems include a ventilation unit to introduce fresh air ventilation into the structure. In certain HVAC systems, for example, the ventilation unit may be provided as part of an air conditioner, heater, and/or humidifier/dehumidifier unit used to regulate the temperature and/or humidity within the structure. Typically, the ventilation unit includes one or more air intake and/or exhaust fans that can be activated to channel fresh air into the structure to supplant the existing air. A damper mechanism may be employed to channel air through one or more ducts and/or vents, allowing fresh air to be introduced at selective locations within the structure. In some designs, the ventilation unit may also include a filtration system to filter airborne contaminants that can further diminish the air quality within the structure.
The HVAC system can be equipped with a controller that monitors and regulates the operation of the various system components. The controller may be configured as a stand-alone unit to run all of the components within the system, or can be configured to run selective components along with one or more other controllers within the system. In either design, the controller may include a processor unit such as a CPU/microprocessor that can be configured to receive a number of input parameters that can be used to control one or more system components in a particular manner.
To ensure that the HVAC system provides a sufficient amount of ventilation, a number of organizations have created standards that utilize a number of physical parameters based on the particular building or structure to be ventilated. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE®), for example, has promulgated Standard 62.2-2003, which provides a standard for the amount of ventilation to be maintained within homes based on the total size of the home to be conditioned, and the number of bedrooms or occupants within the home. When implemented properly, these standards provide a means for meeting certain minimum ventilation requirements without over-ventilating the structure, allowing the ventilation unit to provide an acceptable amount of fresh air while conserving energy.
Despite improvements in ventilation standards, installation and programming of the controller still remains a significant obstacle for many users. Adjustment of many prior-art controllers often requires the user to have a threshold understanding of HVAC systems and their operation. In certain designs, for example, the controller may require the user to refer to a table and/or calculate a value and then subsequently input a setup code or other meaningless number into the controller. Since the inputted code or number does not readily correlate with a known physical value, such programming methods are not always intuitive to the user. As a result, such devices are more prone to user error. Accordingly, there is a need in the art to provide a controller equipped with a simplified controller interface that allows the user to input known physical parameters and/or constants directly into the controller.